const firstObject = { sampleData: 'Hello world' }
const secondObject = { moreData: 'foo bar' }
const finalObject = {
firstObject,
secondObject
};
const firstObject = { sampleData: 'Hello world' }
const secondObject = { moreData: 'foo bar' }
const finalObject = Object.assign({}, firstObject, secondObject);
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
Using the spread operator | |
Using Object.assign |
Test name | Executions per second |
---|---|
Using the spread operator | 5225229.5 Ops/sec |
Using Object.assign | 4654577.0 Ops/sec |
Let's break down what's being tested in this JavaScript microbenchmark.
Benchmark Overview
The benchmark is designed to compare the performance of two approaches: using the spread operator (...
) and Object.assign
(with an empty object) for merging objects.
Options Compared
Two options are compared:
...
) to merge two objects into a new one.Object.assign
with an empty object: This involves using the Object.assign()
method to merge two objects, passing an empty object as the first argument.Pros and Cons of Each Approach
Object.assign
with an empty object:Library Used
There is no library explicitly mentioned in the benchmark definition or test cases. However, it's likely that a standard JavaScript implementation (e.g., V8) is used to execute the benchmarks.
Special JS Feature/Syntax
The benchmark uses the spread operator (...
), which is a syntax introduced in ES6+ languages (including modern JavaScript). This feature allows for concise and expressive way of merging objects. However, as mentioned earlier, this may not be supported in older browsers or environments that don't support ES6+ features.
Other Alternatives
In the past, developers might have used other approaches to merge objects, such as:
concat()
method: const finalObject = { ...firstObject }.concat(secondObject);
const finalObject = {}; for (const key in secondObject) { finalObject[key] = secondObject[key]; }
However, these approaches are generally less efficient and less concise than using the spread operator or Object.assign
.
Benchmark Preparation Code
The benchmark preparation code is empty, which means that the test cases assume that the required objects (firstObject
and secondObject
) are already defined and available for use.